#triangleCanvas {
  background-color: #0a0a0a;
  border: 2px solid #2a2a2a;
  cursor: crosshair;
  display: block;
  margin: 0 auto;
  max-width: 100%;
  height: auto;
}
.side-length {
  font-size: 0.8rem;
  color: #aaa;
  margin-left: 6px;
}